Basic Promise fulfill/reject callback of signIn doesn't work

[rikusen0335]

signIn("discord")
  .then((res) => router.push("/bar")
  .catch((res) => {
    console.log("res:", res)
  })

try {
  const state = await signIn("discord")

  console.log("ok?:", state)

  if (state.ok) router.push("/bar")
  else {
    console.log(state)
  }
} catch (e) {
  console.log("err", e)
}

Those basic callback handler, which means almost same code, of Promise fulfill/reject doesn't work.

So I google and read the doc that talking about how to handle the error on the same page, but const state = await signIn("discord") is showing that state is SignInResponse which has { ok: boolean, error: string, ... } etc.

I just wanna know how it works(?) and what's wrong with my codes.

Any information or replies are really appreciated.

Edited:
Okay so my next-auth was really old and I upgraded it. Found v4.6.0 upgrades signIn return types to Promise<SignInResponse | undefined> with "email" | "credentials", either Promise<undefined>.

But I thought it is Promise<> so still fulfill/reject should work as I expected?